io_uring: remove custom ->func handlers

In preparation of getting rid of work.func, this removes almost all
custom instances of it, leaving only io_wq_submit_work() and
io_link_work_cb(). And the last one will be dealt later.

Nothing fancy, just routinely remove *_finish() function and inline
what's left. E.g. remove io_fsync_finish() + inline __io_fsync() into
io_fsync().

As no users of io_req_cancelled() are left, delete it as well. The patch
adds extra switch lookup on cold-ish path, but that's overweighted by
nice diffstat and other benefits of the following patches.
Signed-off-by: NPavel Begunkov <asml.silence@gmail.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -2898,23 +2898,15 @@ static int io_prep_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	return 0;
 }
 
-static bool io_req_cancelled(struct io_kiocb *req)
-{
-	if (req->work.flags & IO_WQ_WORK_CANCEL) {
-		req_set_fail_links(req);
-		io_cqring_add_event(req, -ECANCELED);
-		io_put_req(req);
-		return true;
-	}
-
-	return false;
-}
-
-static void __io_fsync(struct io_kiocb *req)
+static int io_fsync(struct io_kiocb *req, bool force_nonblock)
 {
 	loff_t end = req->sync.off + req->sync.len;
 	int ret;
 
+	/* fsync always requires a blocking context */
+	if (force_nonblock)
+		return -EAGAIN;
+
 	ret = vfs_fsync_range(req->file, req->sync.off,
 				end > 0 ? end : LLONG_MAX,
 				req->sync.flags & IORING_FSYNC_DATASYNC);
@@ -2922,53 +2914,9 @@ static void __io_fsync(struct io_kiocb *req)
 		req_set_fail_links(req);
 	io_cqring_add_event(req, ret);
 	io_put_req(req);
-}
-
-static void io_fsync_finish(struct io_wq_work **workptr)
-{
-	struct io_kiocb *req = container_of(*workptr, struct io_kiocb, work);
-
-	if (io_req_cancelled(req))
-		return;
-	__io_fsync(req);
-	io_steal_work(req, workptr);
-}
-
-static int io_fsync(struct io_kiocb *req, bool force_nonblock)
-{
-	/* fsync always requires a blocking context */
-	if (force_nonblock) {
-		req->work.func = io_fsync_finish;
-		return -EAGAIN;
-	}
-	__io_fsync(req);
 	return 0;
 }
 
-static void __io_fallocate(struct io_kiocb *req)
-{
-	int ret;
-
-	current->signal->rlim[RLIMIT_FSIZE].rlim_cur = req->fsize;
-	ret = vfs_fallocate(req->file, req->sync.mode, req->sync.off,
-				req->sync.len);
-	current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
-	if (ret < 0)
-		req_set_fail_links(req);
-	io_cqring_add_event(req, ret);
-	io_put_req(req);
-}
-
-static void io_fallocate_finish(struct io_wq_work **workptr)
-{
-	struct io_kiocb *req = container_of(*workptr, struct io_kiocb, work);
-
-	if (io_req_cancelled(req))
-		return;
-	__io_fallocate(req);
-	io_steal_work(req, workptr);
-}
-
 static int io_fallocate_prep(struct io_kiocb *req,
 			     const struct io_uring_sqe *sqe)
 {
@@ -2986,13 +2934,20 @@ static int io_fallocate_prep(struct io_kiocb *req,
 
 static int io_fallocate(struct io_kiocb *req, bool force_nonblock)
 {
+	int ret;
+
 	/* fallocate always requiring blocking context */
-	if (force_nonblock) {
-		req->work.func = io_fallocate_finish;
+	if (force_nonblock)
 		return -EAGAIN;
-	}
 
-	__io_fallocate(req);
+	current->signal->rlim[RLIMIT_FSIZE].rlim_cur = req->fsize;
+	ret = vfs_fallocate(req->file, req->sync.mode, req->sync.off,
+				req->sync.len);
+	current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
+	if (ret < 0)
+		req_set_fail_links(req);
+	io_cqring_add_event(req, ret);
+	io_put_req(req);
 	return 0;
 }
 
@@ -3489,38 +3444,20 @@ static int io_prep_sfr(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	return 0;
 }
 
-static void __io_sync_file_range(struct io_kiocb *req)
+static int io_sync_file_range(struct io_kiocb *req, bool force_nonblock)
 {
 	int ret;
 
+	/* sync_file_range always requires a blocking context */
+	if (force_nonblock)
+		return -EAGAIN;
+
 	ret = sync_file_range(req->file, req->sync.off, req->sync.len,
 				req->sync.flags);
 	if (ret < 0)
 		req_set_fail_links(req);
 	io_cqring_add_event(req, ret);
 	io_put_req(req);
-}
-
-
-static void io_sync_file_range_finish(struct io_wq_work **workptr)
-{
-	struct io_kiocb *req = container_of(*workptr, struct io_kiocb, work);
-
-	if (io_req_cancelled(req))
-		return;
-	__io_sync_file_range(req);
-	io_steal_work(req, workptr);
-}
-
-static int io_sync_file_range(struct io_kiocb *req, bool force_nonblock)
-{
-	/* sync_file_range always requires a blocking context */
-	if (force_nonblock) {
-		req->work.func = io_sync_file_range_finish;
-		return -EAGAIN;
-	}
-
-	__io_sync_file_range(req);
 	return 0;
 }
 
@@ -3942,49 +3879,27 @@ static int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	return 0;
 }
 
-static int __io_accept(struct io_kiocb *req, bool force_nonblock)
+static int io_accept(struct io_kiocb *req, bool force_nonblock)
 {
 	struct io_accept *accept = &req->accept;
-	unsigned file_flags;
+	unsigned int file_flags = force_nonblock ? O_NONBLOCK : 0;
 	int ret;
 
-	file_flags = force_nonblock ? O_NONBLOCK : 0;
 	ret = __sys_accept4_file(req->file, file_flags, accept->addr,
 					accept->addr_len, accept->flags,
 					accept->nofile);
 	if (ret == -EAGAIN && force_nonblock)
 		return -EAGAIN;
-	if (ret == -ERESTARTSYS)
-		ret = -EINTR;
-	if (ret < 0)
+	if (ret < 0) {
+		if (ret == -ERESTARTSYS)
+			ret = -EINTR;
 		req_set_fail_links(req);
+	}
 	io_cqring_add_event(req, ret);
 	io_put_req(req);
 	return 0;
 }
 
-static void io_accept_finish(struct io_wq_work **workptr)
-{
-	struct io_kiocb *req = container_of(*workptr, struct io_kiocb, work);
-
-	if (io_req_cancelled(req))
-		return;
-	__io_accept(req, false);
-	io_steal_work(req, workptr);
-}
-
-static int io_accept(struct io_kiocb *req, bool force_nonblock)
-{
-	int ret;
-
-	ret = __io_accept(req, force_nonblock);
-	if (ret == -EAGAIN && force_nonblock) {
-		req->work.func = io_accept_finish;
-		return -EAGAIN;
-	}
-	return 0;
-}
-
 static int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
 	struct io_connect *conn = &req->connect;